@xpqz Yes I did! Thank you. I was wondering how you got around using thorn to format your result and had a hunch it might have something to do with those settings (incidentally, I later realized all the settings are linked in the Primer section of tryapl.org).
Typically scan, both left and right variants, are O(n) in both space and time. However it seems that APL's \ operator is like scanl but seems to behave differently in that it is right associative and runs over the array each time, making it O(n^2).
For example,
nums ← 10?10 ⍝ 1 7 4 5 10 3 9 6 2 ...
Following from my previous question, it seems that APL performs a scanl in O(n^2) but the compiler is smart enough to optimize for simple primitives. What then is the best strategy to apply \ to non-simple functions? Additionally, there are many cases when the right associativity does affect the ...
@xpqz BTW, I see people using a lot of NGET etc. to read in files ( @abrudz apparently has some tricks to share soon, and ]get in 18.2 will be nice), but if you're interested in speed, I've been using HttpCommand: github.com/rikedyp/Advent-of-Code/blob/main/kit/pget.aplf
Announcement: Dyalog is looking for beta testers for our yearly problem solving competition. While you can use any language to solve the problems, we prefer if you use an APL, or at least an array-oriented language. You will be expected to give feedback on the 10 easy and ≤10 harder problems, while rating their relative difficulties. Note that by beta-testing, you disqualify from the competition. Let me know if you're interested.
Yes indeed! I was asking because I wondering how it would look if the the glyph was in the middle and the the dyadic name on the left with the monadic name on the right.
Another reason for putting the glyph in the center is that the way it looks now, the dyadic name is much closer to the glyph on the right than the glyph on the left, which to me is a bit confusing
The Dyalog reference card is very small type face, and way too much stuff on it for the beginner. I'm teaching a class next year to some high school students, and would really like a version of this on heavy plastic card stock.
I'll look into that...
I'm also wondering where to draw the line. Between just the primitives and the comprehensive Dyalog version. I'd like to see the dfns syntax, as that is something I teach very early on.
Yeah, now the lines look like + and ⌈ are associated somehow, so either remove them altogether or go back to the darker separator line (which can be more compact too).
CMC: Write a function that takes a single positive integer as argument, and returns all the integers from and including 1 until and including the given integer.
@Fmbalbuena You are reading a global variable (and a!) and printing numbers, rather than defining a function taking an argument and returning a result. This is how you can fix it: Try it online!
Yeah, I've logged a handful of issues against wrong descriptions.
CMC: Given a character scalar representing a primitive function, return a Boolean result indicating if it can be used monadically. E.g. '=' → 0 and '+' → 1
@FawnLocke (Rant: It is an abomination, together with outer product. You could consider bracket axis a hyperator, as it is able to bind with and modify operators like reduce…) Yes, it is.
@PaulMansour It really is. Do you know about my extensions?
Well, bracket axis is ad-hoc, and can do things that are awkward with Rank. This isn't so much an issue with Rank, as much as there being some missing primitives.
That's the problem. I think I remember Dyalog persisting on having primitives have somewhat consistent meaning across arity. Intersection is already quite weird
We have so many open slots for monadic functions, and none at all for dyadic function. I think we could allot a few: ∧ and ∨ for sort ascending/descending ⊥ and ⊤ for conversion from/to binary > and < for increment/decrement ⍷ for type
@FawnLocke Aware, but haven't studied in detail. I like that things like and/or should have extended valance for sorting. I worry about other types of extensions.
@PaulMansour Morten wants to redefine dyadic grade to be sort-by. Geoff said monadic ⊥ and ⊤ are "a waste of a development hole. 2⊥ is short and easy to read and comprehend." I've not raised increment/decrement. I think I've mentioned ⍷ for type but my colleagues don't see the value of that function (evidenced by its removal when we left ⎕ML←0).
I'm generally against breaking changes, but I do advocate redefining scalar⊤ to mean scalar⊥⍣¯1 as I can't imagine anyone using scalar⊤ instead of ⎕CT←0 ⋄ scalar|
@Adám Yes. I'm not smart enough to use key, and always have to fiddle with the results. If I have the indices and the uniques, I can always get what I want.
